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Michi’s blog » archive for February, 2007

 Carnival of mathematics, issue 2

  • February 23rd, 2007
  • 10:14 pm

The second carnival of mathematics is up over at Good Math, Bad Math. It’s again a nice, good read. Go.

The third carnival of mathematics is to be hosted by yours truly on the International Women’s Day (maybe we can get a theme going? Women in mathematics, anyone?). Submissions to me directly or over the submission form.

 The Order of the Science Scouts of Exemplary Repute and Above Average Physique

  • February 20th, 2007
  • 6:18 pm

These badges are also displayed on my About page, but the explanation why merits a blog post of its own.

For one thing, I blog about the stuff. I also was a radio speaker at the time that Radio Unga Forskare was active.

This blog. Do I really need to say more?

I’m an old boy scout. I came 3rd in the national quals for the International Chemistry Olympiad back when. I do know how to handle a flame in a lab.

Freezer? Sure. Who hasn’t?

Dry ice? Of course. Unga Forskare (the association of Young Scientists) responsible for this.

Liquid nitrogen? Oh yes! Favourite pastime among Unga Forskare.

I really do know more computer languages than quite a few people. Then again, there are some who know more than I do, and sure, most of those end up reading this blog, so .. well .. call it a draw, shall we?

 Response to Heath Raftery

  • February 9th, 2007
  • 11:57 pm

While I’m still on the subject of writing code with the PFP library, I may as well join in on a discussion that got pulled into the Carnival of Mathematics exposition.

Heath Raftery writes about weird probabilities in dice discussions, a problem very much reminiscent of the Monty Hall problem, both in the amount of controversy it generates when people discuss it, and also, it seems on at least half the people in the discussion so far, in how much the terms use end up confusing people.

So, in a comment to the Carnival post, the suggestion came from Alex, that a simulation be used to settle the whole question. And since I just wrote some things with PFP, I might as well write another!

The question, as posed by Heath, is

 More silly random text

  • February 9th, 2007
  • 5:34 pm

Syntaxfree writes over at his blog about a silly little toy he wrote, using the PFP library, to generate random text.

Now, his text is unreadable. I mean, it’s even unpronounceable. Why? Because he’s looking at bigram distributions of letter.

Great, I thought, I’ll do him one better. Random text using bigram distributions on words must surely be a LOT better than random text using bigram distributions on letters. At least the words come out readable, and they may even come out in a decent order.

So I sat down with his code, and hacked, tweaked, and monadized it to this

module Test where

import Probability
import Data.Char
import Control.Monad


bigram t = zip ws (tail ws) where
  ws = (words . map toLower . filter (\x -> isAlpha x || isSpace x)) t

distro = uniform . bigram

 First carnival of mathematics is up!

  • February 9th, 2007
  • 1:47 pm

Over at Alon’s place, Abstract Nonsense, the first issue of the forthnightly Carnival of Mathematics is up.

Go there. Read. There’s a LOT of good blog posts there.

 D8 revisited

  • February 7th, 2007
  • 6:36 pm

I have previously calculated the A-structure for the cohomology ring of D8. Now, while trying to figure out how to make my work continue from here, I tried working out what algebra this would have come from, assuming that I can adapt Keller’s higher multiplication theorem to group algebras.

A success here would be very good news indeed, since for one it would indicate that such an adaptation should be possible, and for another it would possibly give me a way to lend strength both to the previous calculation and to a conjecture I have in the calculation of group cohomology with A means.

So, we start. We recover, from the previous post, the structure of the cohomology ring as k[x,y,z]/(xy), with x,y in degree 1, and z in degree 2. Furthermore, we have a higher operation, m4, with m4(x,y,x,y)=m4(y,x,y,x)=z.

 Announcing the Carnival of Mathematics

  • February 2nd, 2007
  • 11:09 am

Alon Levy, over at Abstract Nonsense has just announced the first issue of a brand new Blog Carnival: the Carnival of Mathematics.

Go take a look. Submit your own blog posts. And then check it out in a week – the carnival is scheduled for the 9th.